//具名导出
export let add = (a,b)=>{
    return a + b
}
console.log(add(15,20))

//默认导出
let sub = (a,b)=>{
    return a - b
}
export default sub 
console.log(sub(20,6))

//统一导出
let x = 100
let y = 200
let sum = (a,b)=>{
    return a * b
}
export {x,y,sum}
console.log(sum(4,17))